Lay up periods are the way to go. Do not completely cancel your insurance! Lay up periods say you cant use the boat but if the building it's in catches fire it is still covered.
It also kind of depends on the boat. On my cat I had a lay up period of 5 months and it saved me about $3000 a year. On a single engine v-hull it might only save you $100-200 a year.
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